3) if I'm NOT mistaken, these holders look a lot like a baseball card "snap" holder with an adhesive button for the hook. The wood appears to be a shaped piece of oak with a simple saw kerf, then stained.

You'd be right on there.

If I had the tools, and knowledge, i'd make them myself, but i have neither. If you know of someone who is interested to knock up a few more of the wood blocks, i'm all ears. the snap holders are easy to source.